Such a method is known for example from DE 10 2005 048 579 A1.
With this known apparatus the dry separation of the wet-paint overspray from the crude gas stream of a spray booth is effected in a filtering apparatus after a flowable, particulate auxiliary material, known as a “precoat” material, has previously been delivered into the crude gas stream by means of a nozzle arrangement.
The purpose of this auxiliary material is to deposit as a barrier layer on the surfaces of the filter element in order to prevent these areas from becoming clogged by adhering overspray particles. By periodic cleaning of the filter elements of the filtering apparatus the mixture of auxiliary material and wet-paint overspray passes from the filter elements into an auxiliary-material receiving container, from which it may be extracted in order to be fed to the nozzle arrangement for reuse as auxiliary material. The mixture of auxiliary material and wet-paint overspray that is situated in the auxiliary-material receiving container may moreover be swirled up by means of compressed air pulses from a compressed air lance so that it may then rise from the auxiliary-material receiving container up to the filter elements and deposit there.
With this known method there is a risk that in the event of improper operation auxiliary material may pass into the application region of a paint shop, in which the crude gas stream is charged with the wet-paint overspray.